The present invention relates to a die mold for the production of injection molded products of thermoplastic synthetic material, particularly fittings, each fitting having a longitudinal axis and a flanged end, with a single-piece ring, particularly a ring-shaped flange, nonremovably mounted about the flanged end of the fitting. More particularly, the present invention relates to such a die mold including mold components separable along a plane extending parallel to the longitudinal axis of a fitting to be produced, the components having formed therein a recess into which is inserted the ring prepatory to and during a molding operation, and a closure member for closing such recess, the closure member being divided around the periphery thereof into plural portions and the closure member forming a wall of the die mold in the closed position of the mold components.
A fitting made of a synthetic material generally includes a pipe-shaped portion or element, on one end of which is formed a bulged portion defining a bead configured for fitting of a sealing ring, and the other end of which has a flange. In order to connect the flanged end of the fitting to a mounting or to another pipe-shaped element, there generally is provided an undivided ring-shaped flange fitted around the pipe element. In order to mount such single-piece ring-shaped flange about the fitting, it has been customary to heat the synthetic material so that the single-piece ring-shaped flange may be fit over the bulged end after compressing the same. However, in addition to the large amount of time and energy (heating of the fitting) required, this known procedure in most cases results in permanent deformation which has a very detrimental effect on the sealing of the fitting.
In order to avoid such disadvantages it has been proposed, as disclosed in Austrian Patent No. 362,140, to provide the mold components with a recess into which is fitted the single-piece ring and to close such recess during a molding operation by a closure member divided into separable portions around the periphery thereof. The closure member is inserted into the recess such that the inner surfaces of the plural portions of the closure member form a wall of the die mold in the closed position of the mold components. This arrangement however also provided that the closure member was divided axially of the longitudinal axis of the fitting to be produced, and this results in a complicated arrangement.